The Continent is enjoying a jazz age this summer like no other. This weekend, for example, there are festivals in Paris, Montreux, Istanbul, The Hague, Nice, Perugia, and Pori, Finland. Courtney Pine, Chick Corea, Ray Charles, Wynton Marsalis, and Joshua Redman are all crossing the pond to lug their equipment from stazione to gare to aeroporto right through the summer.
So what has turned an American minority art form into a European crowd- pulling tourist venture, which fills Roman amphitheatres, old bullrings, and suburban parks with foot-stomping feelgood boppers? The answer lies in the very nature of jazz - and in the place that Europe has become.
The boundaries that once caused our western European neighbours to spend their days in wars and skirmishes are breaking down, as are the conventions and codes that once shaped ways of life across the continent. With the old rigidity gone, what better backing track for the new dispensation than the melting-pot music of the Americas, with its innovation and improvisation? The push and pull of splitting rhythm and melody that gives jazz its spontaneity and adaptability suits the mood.
How different it is in America today. Jazz captured the mood of the States at a time when it was a land of refugees, exiles and emigrants making do and making sense of who they were and what sort of nation they were becoming. However many stars there were, jazz was always about a band working together, helping the audience make sense of an individual soloist's flight of improvisational fancy. It offered a sense of freedom. And above all it was - still is - about taking influences, bending and shaping them, and developing a response between musicians and audience. Now as the United States grows in power with its all-conquering Coca- cola culture, jazz with its rebel heart no longer seems the right soundtrack. Leave that to stadium rock.
Of course, jazz's increasing popularity in Europe also means that the music, or at least its roots, are coming home. Influenced by classical music, marches, spirituals, work songs, ragtime and blues, jazz combined African and European tradition when it first became a distinctive form.
This summer's festivals offer Dixieland and swing, the fast, hard-hitting rhythms of bop, the mellow harmonies of cool jazz, the avant-garde and jittery, atonal free jazz. Numbers like "Straight, No Chaser" and "One Bourbon, One Scotch, One Beer" have come out the smoky bars where they were first played to become the sounds we savour on lazy days over glasses of chilled wine and jugs of iced beer.
But at its unpredictable, risky heart is something else, a melancholic, meditative foundation - the blues. No wonder it seems to suit Europe's mood. We enjoy the fun of jazz, the way it urges us to live for the moment, to relish every emotion; but we still know that the old stabilities have gone, that the old terrors of warfare, though banished from the west for 50 years, are not so far away at all. Perhaps that is why we sit back and listen in the sticky heat rather than dance the night away in places like San Sebastian. The passion is always measured.
It's not the first time that jazz has lost its connection to dance: in Forties America , a prohibitive entertainment tax closed many dance halls and the growing popularity of pop singers doomed the big bands, while the elimination of dance floors at many clubs made jazz into a music strictly for listening to.
But if we turn jazz into nothing more than lounge music, it will lose its heart. Jazz can get complacent - bogged down in cliched arrangements - as happened in the era of swing. Wynton Marsalis preaches very hard about the fact that jazz musicians have turned off more audiences by being too self-indulgent in their improvisations. Save those 30 minute blow- out tunes for rehearsals or jam sessions! Far too many jazz musicians have fallen into a hypnotic state, induced by John Coltrane's singular example in the 1960s.
Then there are the times when a band can be tempted to play the same tunes at every performance. Predictability should be the enemy of every jazz musician and festival organiser, for jazz is an art form whose hallmark is its spontaneity. There is that dread moment in the worst performances when you realise that for each tune, the sequence of solos is the same, everybody in the quartet plays an extended solo, and each piece lasts 15 minutes. And that, of course, is the danger of jazz festivals - that the musicians will take no risk, offering a bland repertoire to please such varied crowds of all generations.
Jazz is now very much an international music, with some of the most stimulating sounds of recent times coming from Europe. But it's not clear which direction it will take in the future (some cynics even think the music has essentially reached the end of its development). But as long as players with their need for self-expression just keep playing, jazz will survive.
And when festival organisers do take a gamble, the audience often loves it. Who would think, for example, that one of the most successful jazz fesitvals takes place each year in suburban west London, when Ealing hosts a free week-long feast? The bands that play fusion do just as well as any playing safer version of jazz. When the audience is as eclectic as the music, the result is the only thing about the event that is predictable - the applause doesn't stop, and nobody wants to go home.
Yet despite its success, this kind of event is much less popular in Britain than it is on the Continent. The English have yet to learn the coolness of their neighbours. Instead, we are a nation in which summer nights are filled with the sound of country-house opera. Consider the winning formula: you run an expensive country home, so you charge people to belong to a waiting list, and then another fee for pricey tickets. You persuade people to wear fancy clothes, spend hours in traffic jams trying to get out of London in order to listen to La Boheme, with a lengthy interruption for smoked salmon and a glass of Moet. It's a perfect formula for corporate hospitality. The usual 90-minute interval is ideal for entertaining and buttering up clients.
No matter if they loathe the music: by the second half they are too sozzled to notice. The only soundtrack they require is the whispered schmoozing of their hosts. Result: a wealthier house-owner, satisfied businessmen, and a magnificent vehicle for ostentatious displays of wealth and position. Class still counts during a British country summer.
Compare that to the long, louche days people spend at Europe's jazz festivals. There's no attempt at dressing for the occasion, no desire to impress, no sidelong glances to see who has dined with whom, and who is wearing what. Jazz suits summer: it is music that embodies freedom, embraces the sensual and celebrates living for the moment. As Duke Ellington put it: "I have fun. My thing is having fun."